Assessment of Electromagnetic Exposure from 5G Mobile Radio in Public Transportation Systems

The progressive development of intelligent transportation systems implies an increasing exposure to high-frequency sources. From a radiation protection perspective, this development necessitates systematic assessment campaigns. In this paper, we present and discuss exposimetry studies of the instantaneous exposure to passengers riding two types of public transportation buses (conventional, and automated according to SAE level 2, electrical drive). By comparison with results from outdoor measurements, the impact of signal attenuation by the bus windows become apparent. All measured exposure levels remained well below the ICNIRP reference levels, on average 0.4...0.9%. The study revealed that an increase of field exposure is not necessarily linked to the installation of additional radio sources but depends markedly on the data traffic originating from other passengers. Further investigations regarding scenarios with intense use of mobile phones revealed a total exposure ratio between 0.02% and 1.1%, indicating safe conditions in all scenarios at the present state of installations.